Glycoprotein IIb/IIIa receptor blockade improved acetylcholine-induced vasodilation and L-NMMA responses in patients with symptomatic coronary artery disease.
Does glycoprotein IIb/IIIa receptor blockade improve endothelial vasomotor function and NO bioactivity in patients with symptomatic coronary artery disease?
Glycoprotein IIb/IIIa receptor blockade acutely improves endothelial function and nitric oxide bioavailability in patients with coronary artery disease, suggesting a mechanism for its microvascular benefits.
BACKGROUND: Platelet glycoprotein IIb/IIIa receptor blockade not only enhances epicardial flow but also improves microvascular perfusion. Inhibition of abnormal platelet-endothelial interactions may contribute to this beneficial effect. The present study was designed to determine whether glycoprotein IIb/IIIa receptor blockade influences endothelial vasomotor function and NO bioactivity in patients with coronary artery disease. METHODS AND RESULTS: Forty patients with symptomatic coronary artery stenosis were studied before planned percutaneous coronary intervention. By using venous occlusion plethysmography, endothelium-dependent and -independent vasodilation was determined by measuring forearm blood flow responses to acetylcholine with and without NG-monomethyl-L-arginine (L-NMMA) and sodium nitroprusside. Vascular function tests were repeated during glycoprotein IIb/IIIa receptor blockade by tirofiban in 27 patients and by eptifibatide in 13 patients. A subgroup of 10 patients was retested 6 hours after stopping infusion of tirofiban. Glycoprotein IIb/IIIa receptor blockade by both substances improved acetylcholine-induced vasodilation and L-NMMA responses. Six hours after withdrawal of tirofiban infusion, the beneficial effects were not evident. Sodium nitroprusside-induced vasodilation was not changed by glycoprotein IIb/IIIa receptor blockade. CONCLUSIONS: These findings support the concept that abnormal platelet-endothelial interactions contribute to endothelial dysfunction and impaired NO bioactivity in patients with symptomatic coronary artery disease.
Heitzer et al. (Tue,) conducted a other in Coronary artery disease (n=40). Glycoprotein IIb/IIIa receptor blockade (tirofiban or eptifibatide) vs. Baseline (before blockade) was evaluated on Endothelium-dependent and -independent vasodilation (forearm blood flow responses). Glycoprotein IIb/IIIa receptor blockade improved acetylcholine-induced vasodilation and L-NMMA responses in patients with symptomatic coronary artery disease.